Definitions

1. noun

A hard object, such as a stone or pebble, swallowed by an animal, especially a bird, to aid in digestion.

“Some birds are known to ingest gastroliths to help grind up their food in their gizzard.”

2. noun

A hard object, especially a stone, used by an animal to aid in grinding or crushing food in the digestive system.

“The fossilized remains of gastroliths have been found in the stomachs of some extinct dinosaurs.”